let str="abc";
let str2="123456789";
const LIMIT=8;


//1.把字符串以长度8切分，
//2.不够8的补0
let index=0;
while (index<str2.length) {
    let ele=str2.substring(index,index+=LIMIT);//截取长度8字符串
    console.log(ele.padEnd(LIMIT,"0"));//不够长度8的补零
}


